Related research by Michael Hammer of the University of Arizona examined the Y-chromosomes of Jewish men who identified themselves as Cohanim the priestly caste and found over a decade ago that the vast majority had a common ancestor who lived in early Biblical times.

Somebody would have to do the math, but I think if you had a population that had a higher percentage of Rh- mixing with a population with a lower percentage of Rh-, then Y-chromosomes common in the Rh- population would expand at the expense of the Y-chromosomes in the more Rh+ population.

The premise of the article very simplified is that the prevalence of Germanic stock Y-chromosomes in modern Britain is out of all proportion to the evidence we have for the number of Anglo-Saxon invaders.